Piano-playing mechanism and the like.



A. R. TRIST. PIANO PLAYING MECHANISM AND THE LIKE.APPLIOATION'FILEDJAN.5,191&

' Patented Nov. 21, 1911.

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UNITED STATES PATENT OFFICE.

ARTHUR RONALD TRIST, OF LONDON, ENGLAND, ASSIGNOR TO TRIST PIANO PLAYERLIMITED, OF LONDON, ENGLAND.

PIANO-PLAYING MECHANISM AND THE LIKE.

Specification of Letters Patent.

Patented Nov. 21, 1911.

Application filed January 5, 1910. Serial No. 536,535.

To all whom it may concern:

Be it known that I, ARTHUR RONALD Tmsr, a subject of the King of GreatBritain and Ireland, residing at London, England, have invented new anduseful Improvements in and Relating to Piano-Playing Mechanism and theLike, of which the following is a specification.

This invention relates to piano-playing mechanism and has for its objectthe provision of means for accentuating certain notes, for example, themelody of the composition being played, and further the construction ofthe mechanism in a simple and effective manner. The record sheet bywhich the operation is controlled may be of any form in which specificnotes can be defined, so that the note perforations or confacts in thecase of electrical operating mechanism control the amount of impact ofthe striking mechanism of each note respectively.

To carry the invention into effect I arrange the piano-playing apparatuswith two systems of air pressure which may be either on a plenum or avacuum system or a combination of the two, and I arrange two sets ofprimary valves one set controlled by the tracker mechanism for ordinarynotes and the other set by the tracker mechanism for the accentuatednotes in conjunction with a record music sheet. In connection with eachset of primary valves I arrange a set of secondary valves one set beingconnected to the high pressure reservoir and the other to the lowpressure reservoir.

Both sets of secondary valves are connected to the pneumatic motorelements of the striking mechanism and each said mechanism isprovidedwith an automatic control or intercepting valve arranged so thatwhen one secondary valve is moved by the air pressure controlled by itsparticular primary valve, such air pressure operates the interceptingvalve and cuts off all communication between the pneumatic motor elementand the secondary valve of the other pressure, thus allowing only theparticular pressure of air controlled by the primary valve to operate onthe pneumatic motor ele ment so as to produce the desired efiect. Inthis way the pressure of air used is that selected. by the record sheetin operating any high or low pressure primary valve as the case may be.

In order to reduce the volume taken up by the striking mechanism and itsvarious parts, instead of using pneumatics of the ordinary bellows type,I form each motor element as a piston sliding within a cylin der. Thewhole of the air containing parts of the apparatus are constructed inmetal, vulcanite or other impermeable material. To this end I arrangethe cylinders of the motor elements in a row along the length of a frameor body and on each side I arrange the high and low pressure secondaryvalves respectively. In the passage between the said high and lowpressure secondary valves leading to the motor element I arrange theintercepting valve which is adapt ed to co-act with two seatings oneleading to the high pressure secondary valve chamber and the other tothe low pressure secondary valve chamber. It will thus be seen thatwhere one secondary valve say the low pressure, is operated, thedifference of pressure set up on the two sides of the intercept ingvalve will close the intercepting valve on the seating leading to thehigh pressure secondary valve and allow the low pressure air to act onthe motor element and vice versa.

In order that the invention may be the better understood I will nowdescribe the same in relation to the accompanying drawings, referencebeing had to the letters and figures marked thereon.

Like letters refer to like parts in the various figures.

Figure 1 is a plan view of the complete action for one note. Fig. 2 is apart sectional elevation on the line 2-2 of Fig. 1, including adiagrammatic representation of the electrical arrangements, circuits,and tracker board in connection with a music sheet.

In order to carry out my invention in reference to the piano-playingmechanism I will describe it in relation to mechanism in which vacua oftwo different pressures are used and in which one pressure is controlledpneumatically and the other pres sure is controlled electrically.

Referring to Figs. 1 and 2 a is the low pressure vacuum chest and b isthe high pressure vacuum chest having secondary valves a Z2respectively. These valves are controlled in the usual Way by means ofprimary valves 0 and cl respectively. The valve 0 is controlled by anelectrically operated valve 6, while the valve (Z is controlled by thetracker f through the connecting pipe 9 leading to the primary valve (Zof usual construction. Disposed between the secondary valves a b is anintercepting valve in which has two valve faces disposed opposite to oneanother adapted to bear against the valve seats 7L [1. arranged on thedividing partition if. A passage leads from the secondary valves to thepower pneumatic is which is connected to the keys by the usual means Z.The trunks m m are connected with the atmosphere. The music sheet awhich may be of the form in which an electrically conducting layer a andpneumatic perforations a are provided, the conducting layer beingexposed for certain notes so that electrical contact can be made, thusenabling two different and independent mechanisms to be operated by thecontrol of the music sheet. Above the tracker f is arranged an insulatedsupport carrying a series of brushes 0 one only being shown, and eachbrush is included in a circuit comprising a source of current 7) and anelectromagnetic device 1 adapted to operate the valve 6 through a lever9 The operation is then as followsz-JVhen during the passage of themusic sheet on the tracker f the perforation a uncovers the hole in thetracker the primary valve (Z is actuated and in turn actuates thesecondary valve 6 in the usual manner. This action permit-s thedifference of pressure set up by the vacuum to act upon the interceptingvalve 7L so that it comes off its seat 7L and closes down on the seat7%, thus putting the pneumatic 76 into direct communication with thehigh pressure vacuum and causing the note to be sounded loudly. As themovement of the sheet progresses the brush 0 comes in contact with theexposed metallic layer a and completes the electric circuit. This causesthe electromagnetic device 9 to open the valve 6 and to admit air to theprimary valve 0 which in turn allows the secondary valve a to beoperated, and the low pressure vacuum to draw the intercepting valve tothe right of the seat It immediatedy the perforation a on the musicsheet has passed away from the hole in the tracker f. In this way thenote is held on for the required time.

It will be understood that when no perforation occurs in any note on themusic sheet but only the metallic layer is exposed, the primary valve 0and seconardy valve a are the only ones operated in which case the noteis sounded with the low pressure vacuum.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is In piano playing mechanism, the combination ofpneumatically operated playing mechanism including power pneumatics, twowind chests for different pressure of wind and tracker means andconnections for controlling individually the pressure of wind to eachpower pneumatic by the perforation. in the music sheet, with a set ofcontrol valves for each wind chest for controlling the operation of eachpower pneumatic of the playing mechanism, and a three way check valvedisposed between the said two sets of control valves and the powerpneumatics constructed to automatically cut olf one pressure supply andput into action the other pressure supply as selected by the music sheetby the direct application of the pressure selected acting upon saidintercepting valve, substantially as described.

In testimony whereof, I have signed my name to this specification in thepresence of two subscribing witnesses.

ARTHUR RONALD TRIST. Witnesses:

H. D. J AMESON, T. L. RAND.

Copies of this patent maybe obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. C. v

